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The Quark Theory
Introduction Over the years of physicists exploring the anatomy of the nucleus, a host of particles were discovered. The function of these exhumed particles were "largely unknown". A number of theories were developed in attempt to explain the existance of these particles. One of the most successful models to explain the particles' existance is the Standard Model. The Standard Model The Standard Model assumes that four fundamental interactions operate in the universe. These four fundamental interactions, also known as fundamental forces, are electromagnetic, weak, strong, and gravitational. The Standard Model identifies its behavior and relationships with the electromagnetic, strong, and weak interactions. Strong Interaction Strong interaction is the force that holds the protons and neutrons together in an atom's nucleus. Weak Interaction Weak interaction is a force present in the nucleus of an atom during radioactive decay. The weak nuclear force is the explanation of the decay of neutrons into protons and protons into neutrons. Attempts to prove the gravitational force as a medium of interaction in The Standard Model has not been successful. In addition to the fundamental interaction there are fundamental particles, known as quarks, which are theorized by physicists to make up the matter of protonshttp://en.wikipedia.org/wiki/Proton, neutronshttp://en.wikipedia.org/wiki/Neutron, and other nuclear particles. Quarks Quarks have fractional element charges. There are six identified variaties of quarks. The six quarks are Up, Down, Charm, Strange, Top, and Bottom. Each quark name identifies with its property. Each property is known as a flavor. Below is the table of all six quark properties and their charges. The energies listed above are used by physicists to determine the charge of a particle, such as a proton or a neutron. The energies needed to reduce subatomic particles into their referenced quarks are so high that the charge values of these quarks cannot be isolated as separate particles. Their existance can only be demonstrated by indirect means. The Quark Theory is an idea that demonstrates the matter of subatomic particles. Scientists today continue to search for the measurements of the undefined quark values and whether they represent the ultimate structure of matter or if there are even smaller subunits of measure. Practice Problems Using the Quark Table, one can calculate the quark structure of a subatomic particle. Quarks are observed to occur in combinations of two quarks (mesons), three quarks (baryons), and five quarks (pentaquark). Below is a diagram of a radioactive decay, illustrating the structure of the proton and neutron quark structures (two bayrons) transforming into a penaquark through the medium of the strong interaction.: 1. A proton has the structure uud (Up + Up + Down). Referencing the Quark Table, one obtains the charge value of Up= +⅔ e, and the charge value of Down= −⅓ e. Proton= uud= e)+(+⅔ e)+(−⅓ e)= 1 e 2. A neutron has the stucture udd (Up + Down + Down). Neutron= udd= e)+(−⅓ e)+(−⅓ e)= 0 e Resources *Lazar, Miriam A.Barron's Review Course Series; Let's Review: Physics. 3rd. Hauppauge, NY: Barron's Educational Series, Inc., 2004.